with additional static sealing between the sealing, or its casing or support, and the surface on which it is mounted

Full Title

Sealings > between relatively-moving surfaces (F16J15/50, F16J15/52 take precedence; bellows pistons F16J3/06; piston-rings or ring sealings of similar construction F16J9/00) > with elastic sealings, e.g. O-rings > Mounting of sealing rings > with additional static sealing between the sealing, or its casing or support, and the surface on which it is mounted